1. Field of the Invention
The present invention relates to methods and apparatus for monitoring video receivers and identifying the viewing habits of the public, and more particularly to a method and apparatus for identifying the operational status of a video casette recorder.
2. Description of the Prior Art
Various arrangements have been employed to determine both the channel to which a television receiver is tuned and the operational status of a video recorder. A disadvantage of many known monitoring arrangements is that an internal connection to the video casette recorder (VCR) is required.
For example, U.S. Pat. No. 4,697,209, issued Sep. 29, 1987 to David A. Kiewit and Daozheng Lu discloses a method and apparatus for automatically identifying programs viewed or recorded. The disclosed method and apparatus provides an improved way to identify programs and to monitor the viewing habits of the public. However, identification of the video casette recorder's operational modes requires access to characteristic points in a VCR's circuitry for detecting changes in voltage values.
Providing internal connections to the VCR's circuitry is time consuming and complicated due to the wide range of different VCR's currently being used.